Authorities in Pakistan are sending relief supplies and food to a remote northern region of the country, where at least 20 people have died from a powerful earthquake and aftershock.

Officials in the mountainous region say most of the casualties were caused by landslides, and the fact that the mud-walled houses of the region were easily toppled by the earthquakes.

People in parts of the affected area, located in the rugged Hindu Kush mountain range, are said to be sitting outdoors in extremely cold temperatures.

The government has sent doctors and police teams to remote villages in the badly-affected Mansehra and Balakot districts to provide relief and assess damage. Eyewitnesses say the landslides have blocked some of the main roads, hampering rescue efforts.

The earthquakes, measuring 5.7 and 5.5 on the Richter Scale, were centered about 160 kilometers northwest of Islamabad and were strong enough to be felt in the capital.

The border region where Pakistan, Afghanistan and India meet has some of the world's highest mountains and experiences periodic earthquakes.